Broadband Microwave Measurements and Analysis of Artificial Chiral Materials

This presentation treats the microwave modelling of chiral materials, using the measured results of artificial samples that display chirality. The samples are made by embedding metal helices inside dielectric resin. Using a free-space method with two sets of ellipsoidal reflector antennas and HP8510B automatic network analyser, the material characterisation of the samples has been performed from 4.5 GHz to 19 GHz. The observed strong dispersion of the permittivity, permeability, and chirality parameters can be explained with resonance models for the polarizabilities of the helices. It is noteworthy that the measured chirality reach rather high values, halfway to the theoretical linmit.